1. Field of the Invention
The invention relates to an apparatus for rolling and guiding a directable jet nozzle in which a fixed part of the nozzle has at its posterior extremity a spherical race. A spherical race of a sleeve, constituting the movable race of the nozzle, is capable of displacement against the spherical race of the fixed part of the nozzle. Sealing means are provided between the two spherical races.
2. Description of the Prior Art
Modern military aircraft require activating means to change their attitude which, unlike aerodynamic controls, do not involve a concomitant increase in drag. This requirement has led to the use of directable jet nozzle reactors which make it possible to achieve, depending on the chosen deviation component, a rapid attitude modification. Among the known types of directable nozzles, those with a spherical articulation allow orientation in all directions, are less bulky, and are simpler to produce. Applicants' French application Ser. No. 79.29208 filed Nov. 23, 1979 describes a directable jet nozzle with a spherical articulation having a movable part consisting of a cylindrical jet deviation sleeve extended by two coaxial spherical interior and exterior sliding surfaces, and a fixed part formed by the extremity of the ejection duct extended by a spherical surface. The interior spherical sliding surface of the movable part works together with a spherical surface supported at the extremity of the thermal protection jacket and assures the sealing of the flow of ejected gas. The exterior spherical sliding surface of the movable part shifts along the spherical sliding surface of the fixed part thereby engaging the extremity of a sealing membrane whose other extremity is attached to the fixed spherical sliding surface.
The spherical sliding surfaces are thin pieces made by metal forming whose dimensional variations due to manufacturing tolerances are relatively important. Furthermore, these thin metal pieces are subjected to vibrations which limit their useful life.